Simon and Conrad.
It seems to me that you maybe are talking about two different parameters when it comes to a clean Tx-signal from the IC-7300.
I get that Simon is referring to splatter from the intended modulation.
I interpret that Conrad is looking at composite noise from a carrier.
I guess you are both correct.
If some kind of static Pre-Distortion is improving the the splatter levels from a SSB transmission it is very nice.
Still, the composite noise will be there in-between the modulation and also outside the modulation BW.
Splatter and composite noise will for sure have very different QRM characteristics on the band.
Can it be that the composite noise seen, is an artifact of the Pre-Distortion process?
Just a thought.....as I have never been deep diving into Pre-Distortion engineering. But usually there is a price to pay, if you are not very cautious with the details, when engineering a solution.
I am sure someone here is more into this and can explain.
73 / Ingolf, SM6FHZ